It is generally considered that in allergic asthma and other atopic diseases of man or anaphylactic shock in animals, several chemical mediators are released from the lung and other tissues cause troubles in living bodies, such as the constriction of smooth muscles, e.g., bronchi, pulmonary artery, etc., and the enhancement of vascular permeability in the skin. As such chemical mediators, there are histamine and SRS-A (slow reacting substance of anaphylaxis). Histamine plays an important role in guinea pig anaphylactic shock but not in allergic asthma in man (Eiser, "Pharmac. Ther.", 17, 239-250(1982)), whereas a number of lines evidence suggest that SRS-A is the most important chemical mediator of allergic asthma in man (Brocklehurst, "J. Physiol.", 151, 416-435(1960); Austen and Orange, "Am. Rev. Resp. Dis.", 12, 423-436(1975); Adams and Lichtenstein, "J. Immunol.", 122, 555-562(1979)).
The development of the medicaments for the prophylaxis, elimination, and reduction of immediate hypersensitivity reactions was performed aiming at inhibiting the production and release of such chemical mediators or antagonizing the action of these chemical mediators. As an inhibitor of histamine release, disodium cromoglycate (DSCG) is well known and as an inhibitor of actions induced by histamine, various anti-histamics are commercially available. On the other hand, SRS-A is known as a slow reactive and long acting chemical mediator while histamine is a rapid acting and short acting chemical mediator, and it has recently been recognized that SRS-A is a mixture of Leukotriens C.sub.4, D.sub.4 and E.sub.4 the structures of which have been clarified by Dr. Samuelsson. SRS-A, i.e., Leukotriens are lipoxigenase products of polyunsaturated fatty acids (in particular, arachidonic acid) and it has been reported that SRS-A has various activities such as enhancement of mucus production, reduction of mucociliary transport, coronary artery constrictor action, reduction of cardiac contractility, etc., in addition to the actions in the above-described allergic reactions. Only a few materials have been known as the medicaments for inhibiting the production and release of SRS-A or the medicaments antagonizing these actions of SRS-A and they have not yet been clinically used.
As the result of various investigations on finding medicaments capable of inhibiting the production and release of SRS-A or medicaments capable of antagonizing the actions of SRS-A, the inventors have discovered that the compounds of this invention as described hereinafter are useful as medicaments capable of very strongly inhibiting the formation and release of SRS-A and/or medicaments capable of antagonizing the actions of SRS-A and the present invention has been attained based on the discovery.